A continuing investigation of the accuracy and utility of emission tomography using single photon emitting radionuclides (as opposed to positron emitters) for quantifying the size of myocardial infarctions and assessing the effectiveness of intervention therapy in modifying te course of acute infarctions. The long-term goal of this research is the development of a technique which can: (1) fully assess the course of an acute myocardial infarction and (2) assess the effects of any applied intervention therapy on that course. Two different techniques are being evaluated: (1) Coded aperture imaging and related multiple pinhole tomographic techniques and (2) Emission computed tomography using a rotating gamma camera. The optimum choice of radiopharmaceuticals to accomplish the project goals is being investigated in conjunction with the tomographic imaging techniques. Both infarct-avid radiopharmaceuticals such as technetium-99m pyrophosphate and cold spot or perfusion agents such as Thallium-201 are being investigated. The spatial and quantitative accuracy of the imaging techniques are being developed and assessed in a quantifrable dog model of acute myocardial infarction and then extended to human studies where their accuracy is being compared to alternative methods of infarct sizing and when possible correlated with post-mortem measurements of infarct size and location.